I know TCT can go bad as early as 20k miles, but is everyone just replacing them as a proactive change out or are you all waiting for the slightest ticking and then changing?

I have an 09 that at about 50K miles I decided to install a Billman TCT. After a few emails back and forth from him, it was apparent that the TCT failure was a matter of "when" not "if". I had no obvious symptoms but I did a preemptive strike and changed it anyway. Never have to worry about it. The engineering of it made sense to me and the quality of what Billman shipped was first class. Would do it again.

It's pretty well known that the OEM TCT will fail eventually, for most of our cars.

The TCT install is one of the easiest things to install on the car. It takes maybe 15 minutes if you're being extremely cautious (like myself).

I replaced mine with one of Billman's GenX even though mine wasn't making any noise. I just wanted piece of mind since my car had about 85k on it at the time. 5k miles later and zero problems (of course).

Changing the oil is more a pain in the butt that installing a TCT, in my opinion. By far, actually.

I know TCT can go bad as early as 20k miles, but is everyone just replacing them as a proactive change out or are you all waiting for the slightest ticking and then changing?

It's a personal decision to decide when you want to do it. Honestly if yours is quiet maximize the use of it and replace it in the future when it starts giving you signals, there's no performance downside, it's just leads to bad noise. Some will last longer than others. Once it starts going south don't even consider replacing it with an OEM unit as some people have had failures quickly afterwards and the parts aren't cheap.